The "Yankees of Europe" (Czechoslovaks) started (1959) and decommissioned (1997) the first underground repository for radioactive waste, and Germans have been disposing of hazardous waste from industrial and municipal sources in salt and potash mines since 1972. Natural geologic environments have safely contained dangerous (radioactive, volatile, flammable, corrosive, etc.) materials underground -without human assistance- for as long as billions of years. Underground disposal is final, and deep geologic repositories need no monitoring or maintenance after closure.
While storage and disposal of radioactive (decaying with time) waste frequently raises inordinate concern, we routinely place hazardous (infinite half-life) waste into landfills. Many of them may release contaminants in unacceptable concentrations and need monitoring for hundreds to thousands of years. About 7 800 contaminated sites in the U.S. are awaiting corrective action and cleanup.
Application of best scientific, engineering, and environmental principles favors underground rather than surface and near-surface disposal of all categories of dangerous waste. Half a century of international experience and a decade of domestic practice at the Waste Isolation Pilot Plant (WIPP) justify confidence in, and expansion of, this final step in hazardous waste management.